Have each SandboxedProcessLauncherDelegate maintain a zygote.

content/browser/child_process_launcher.cc

Index: content/browser/child_process_launcher.cc
diff --git a/content/browser/child_process_launcher.cc b/content/browser/child_process_launcher.cc
index c705b7db4972e4b339d5a84473f90738a63d139a..a02d05e7329ec47fbaae02df9b7ca5606898f568 100644
--- a/content/browser/child_process_launcher.cc
+++ b/content/browser/child_process_launcher.cc
@@ -39,6 +39,7 @@
 #elif defined(OS_POSIX)
 #include "base/memory/singleton.h"
 #include "content/browser/renderer_host/render_sandbox_host_linux.h"
+#include "content/browser/zygote_host/zygote_communication_linux.h"
 #include "content/browser/zygote_host/zygote_host_impl_linux.h"
 #include "content/common/child_process_sandbox_support_impl_linux.h"
 #endif
@@ -53,7 +54,7 @@ namespace content {
 
 namespace {
 
-typedef base::Callback<void(bool,
+typedef base::Callback<void(ZygoteHandle,
 #if defined(OS_ANDROID)
                             base::ScopedFD,
 #endif
@@ -87,7 +88,7 @@ void OnChildProcessStartedAndroid(const NotifyCallback& callback,
       base::Bind(&RecordHistogramsOnLauncherThread, launch_time));
 
   base::Closure callback_on_client_thread(
-      base::Bind(callback, false, base::Passed(&ipcfd),
+      base::Bind(callback, ZygoteHandle(), base::Passed(&ipcfd),
                  base::Passed(base::Process(handle))));
   if (BrowserThread::CurrentlyOn(client_thread_id)) {
     callback_on_client_thread.Run();
@@ -108,15 +109,15 @@ void LaunchOnLauncherThread(const NotifyCallback& callback,
                             base::CommandLine* cmd_line) {
   DCHECK_CURRENTLY_ON(BrowserThread::PROCESS_LAUNCHER);
   scoped_ptr<SandboxedProcessLauncherDelegate> delegate_deleter(delegate);
+#if !defined(OS_ANDROID)
+  ZygoteHandle zygote;
+#endif
 #if defined(OS_WIN)
-  bool use_zygote = false;
   bool launch_elevated = delegate->ShouldLaunchElevated();
 #elif defined(OS_MACOSX)
-  bool use_zygote = false;
   base::EnvironmentMap env = delegate->GetEnvironment();
   base::ScopedFD ipcfd = delegate->TakeIpcFd();
 #elif defined(OS_POSIX) && !defined(OS_ANDROID)
-  bool use_zygote = delegate->ShouldUseZygote();
   base::EnvironmentMap env = delegate->GetEnvironment();
   base::ScopedFD ipcfd = delegate->TakeIpcFd();
 #endif
@@ -199,8 +200,15 @@ void LaunchOnLauncherThread(const NotifyCallback& callback,
   // child termination.
 
 #if !defined(OS_MACOSX)
-  if (use_zygote) {
-    base::ProcessHandle handle = ZygoteHostImpl::GetInstance()->ForkRequest(
+  zygote = nullptr;

[mdempsky, 2015/12/22 21:21:33]

Hm, so if you use

    using ZygoteHandle = std::nullptr_t;

as the stub typedef, then you could just write:

    ZygoteHandle zygote = nullptr;

here and use "nullptr" instead of "ZygoteHandle()" in
OnChildProcessStartedAndroid.  That seems a bit cleaner to me, what do you
think?

(Sorry, I know I suggested the empty struct in the first place. :-))

[Greg K, 2016/01/05 21:42:13]

Done.

+  ZygoteHandle* zygote_handle = delegate->GetZygote();
+  if (zygote_handle) {
+    if (*zygote_handle == nullptr) {

[mdempsky, 2015/12/22 21:21:33]

I'd suggest adding a comment that mentions we're running on the PROCESS_LAUNCHER
thread here, so we don't need to worry about race conditions in the lazy
initialization.

[Greg K, 2016/01/05 21:42:13]

Done.

+      *zygote_handle = new ZygoteCommunication();
+      (*zygote_handle)->Init();
+    }
+    zygote = *zygote_handle;
+    base::ProcessHandle handle = zygote->ForkRequest(
         cmd_line->argv(), std::move(files_to_register), process_type);
     process = base::Process(handle);
   } else
@@ -282,13 +290,11 @@ void LaunchOnLauncherThread(const NotifyCallback& callback,
                                      begin_launch_time);
   }
   BrowserThread::PostTask(client_thread_id, FROM_HERE,
-                          base::Bind(callback,
-                                     use_zygote,
-                                     base::Passed(&process)));
+                          base::Bind(callback, zygote, base::Passed(&process)));
 #endif  // !defined(OS_ANDROID)
 }
 
-void TerminateOnLauncherThread(bool zygote, base::Process process) {
+void TerminateOnLauncherThread(ZygoteHandle zygote, base::Process process) {
   DCHECK_CURRENTLY_ON(BrowserThread::PROCESS_LAUNCHER);
 #if defined(OS_ANDROID)
   VLOG(1) << "ChromeProcess: Stopping process with handle "
@@ -304,7 +310,7 @@ void TerminateOnLauncherThread(bool zygote, base::Process process) {
   if (zygote) {
     // If the renderer was created via a zygote, we have to proxy the reaping
     // through the zygote process.
-    ZygoteHostImpl::GetInstance()->EnsureProcessTerminated(process.Handle());
+    zygote->EnsureProcessTerminated(process.Handle());
   } else
 #endif  // !OS_MACOSX
     base::EnsureProcessTerminated(std::move(process));
@@ -334,7 +340,7 @@ ChildProcessLauncher::ChildProcessLauncher(
     : client_(client),
       termination_status_(base::TERMINATION_STATUS_NORMAL_TERMINATION),
       exit_code_(RESULT_CODE_NORMAL_EXIT),
-      zygote_(false),
+      zygote_(),

[mdempsky, 2015/12/22 21:21:33]

(And explicitly initialize to nullptr here if you change it.)

[Greg K, 2016/01/05 21:42:13]

Done.

       starting_(true),
 #if defined(ADDRESS_SANITIZER) || defined(LEAK_SANITIZER) ||  \
     defined(MEMORY_SANITIZER) || defined(THREAD_SANITIZER) || \
@@ -404,8 +410,8 @@ void ChildProcessLauncher::UpdateTerminationStatus(bool known_dead) {
   DCHECK(CalledOnValidThread());
 #if defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_ANDROID)
   if (zygote_) {
-    termination_status_ = ZygoteHostImpl::GetInstance()->
-        GetTerminationStatus(process_.Handle(), known_dead, &exit_code_);
+    termination_status_ = zygote_->GetTerminationStatus(
+        process_.Handle(), known_dead, &exit_code_);
   } else if (known_dead) {
     termination_status_ =
         base::GetKnownDeadTerminationStatus(process_.Handle(), &exit_code_);
@@ -438,7 +444,7 @@ void ChildProcessLauncher::SetProcessBackgrounded(bool background) {
 void ChildProcessLauncher::DidLaunch(
     base::WeakPtr<ChildProcessLauncher> instance,
     bool terminate_on_shutdown,
-    bool zygote,
+    ZygoteHandle zygote,
 #if defined(OS_ANDROID)
     base::ScopedFD ipcfd,
 #endif
@@ -463,12 +469,11 @@ void ChildProcessLauncher::DidLaunch(
   }
 }
 
-void ChildProcessLauncher::Notify(
-    bool zygote,
+void ChildProcessLauncher::Notify(ZygoteHandle zygote,
 #if defined(OS_ANDROID)
-    base::ScopedFD ipcfd,
+                                  base::ScopedFD ipcfd,
 #endif
-    base::Process process) {
+                                  base::Process process) {
   DCHECK(CalledOnValidThread());
   starting_ = false;
   process_ = std::move(process);